S-91257A934 7/8"-14 x 4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 150,000 psi ensures reliable performance in high-stress industrial environments, reducing the risk of fastener failure.
• Superior corrosion resistance from zinc yellow-chromate plating extends service life in harsh or outdoor conditions, minimizing maintenance needs.
• High hardness rating (Rockwell C33) provides excellent wear resistance and durability under heavy loads and vibration.
• Fine UNF threading with Class 2A fit offers precise, secure fastening and reduced likelihood of loosening in dynamic applications.
• External hex drive design allows for easy installation and removal with standard tools, improving assembly efficiency.
• Partial threading enables optimal grip and clamping force distribution, ideal for components requiring unthreaded shank sections.
• Compliance with industry standards including ASME B18.2.1 and SAE J429 ensures consistent quality and interchangeability.

Professional Applications & Engineering Value

This Grade 8 hex head screw is engineered to address critical challenges in heavy-duty industrial settings, such as construction machinery, automotive assemblies, and structural frameworks. The steel material combined with zinc yellow-chromate plating provides robust protection against corrosion and environmental degradation, extending the lifespan of equipment. The 7/8"-14 UNF fine thread and Class 2A thread fit ensure tight, reliable connections that resist loosening under vibration and dynamic loads. With a 150,000 psi tensile strength and Rockwell C33 hardness, it delivers exceptional durability and load-bearing capacity, making it a trusted choice for applications demanding high-strength fastening solutions and long-term reliability.

Specification Summary & Compliance

This screw features precise Class 2A thread fit and adheres to UNF fine thread standards with a size of 7/8"-14. It is manufactured in compliance with ASME B18.2.1 and SAE J429 specifications, ensuring dimensional accuracy and performance consistency. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting environmental safety and regulatory requirements in global industrial supply chains.